This invention relates to shovel dippers and, more particularly, to a mechanism for restraining slamming of the dipper door. Power shovels have been employed in earth working for many years, being colloquially known in the early years of this century as "steam shovels". These devices were characterized by a dipper, i.e., a box shaped scoop mounted on the end of a stick which pivoted through a vertical arc. At the top of the arc when the dipper or shovel was filled, the entire device was pivoted to one side and the bottom dump door of the dipper opened to release the carried material into a truck or other means for disposition. Thereafter, the door was swung to closed position and, inasmuch as these were heavy, powerful tools intended for rugged work, considerable force was exerted on the door resulting in a clanging during the closing and latching. This often times resulted in deformation of the door or associated confronting portions of the dipper body with the result that there was a loss of seal and material would drain from the dipper during its sideways movement. This is not only wasteful, but could prove dangerous if someone were under the path of movement.
According to the invention, this undesirable phenomenon (of a clanging closure) is avoided through the use of a novel energy dissipation mechanism which features a Belleville spring. The Belleville spring in this environment requires only initial tightening and will continue to perform satisfactorily during a substantial portion of the life of the mechanism.
Other objects and advantages of the invention may be seen in the details of construction and operation set down in the ensuing specification.